Soft gluon emission off a heavy quark revisited

TL;DR

This paper derives an improved suppression factor for gluon emission from heavy quarks in QCD, valid across all rapidities and quark masses, impacting understanding of heavy quark energy loss in heavy-ion collisions.

Contribution

It introduces a generalized suppression factor for gluon emission that extends previous models to all rapidities and mass scales, enhancing theoretical accuracy.

Findings

Reproduces the dead cone effect in forward rapidity

Shows minimal suppression in backward direction

Impacts models of heavy quark energy loss in quark-gluon plasma

Abstract

An improved generalized suppression factor for gluon emission off a heavy quark is derived within perturbative QCD, which is valid for the full range of rapidity of the radiated gluon and also has no restriction on the scaled mass of the quark with its energy. In the appropriate limit it correctly reproduces the usual dead cone factor in the forward rapidity region. On the other hand, this improved suppression factor becomes close to unity in the backward direction. This indicates a small suppression of gluon emission in the backward region, which should have an impact on the phenomenology of heavy quark energy loss in the hot and dense matter produced in ultra-relativistic heavy-ion collisions.